Monitoring device, monitoring method, and recording medium

ABSTRACT

To present a region which is not fully monitored, provided is a monitoring device comprising a detection means, an estimation means, a determination means, and a presentation means. The detection means detects a person from an image. The estimation means estimates a region which is being viewed by the person who is detected by the detection means. On the basis of the region estimated by the estimation means, the determination means determines a region which requires special attention within a monitoring area. The presentation means presents information indicating the region which requires special attention determined by the determination means.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation application of U.S. patentapplication Ser. No. 17/418,423 filed on Jun. 25, 2021, which is aNational Stage of International Application No. PCT/JP2020/000133, filedon Jan. 7, 2020, claiming priority to Japanese Patent Application No.2019-003514, filed on Jan. 11, 2019, the contents of all of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The disclosure relates to a monitoring device, a monitoring method, anda recording medium, and for example, relates to a monitoring device thatanalyzes a video captured by a monitoring camera to support monitoringin a monitoring area by a security guard or another person.

BACKGROUND ART

In a case where a security guard monitors a monitoring area, forexample, monitoring in which the security guard monitors a video inwhich the monitoring area is captured by a monitoring camera andmonitoring performed by the security guard patrolling in the monitoringarea are jointly used.

FIG. 13 is a diagram explaining a monitoring system 1000 described inPTL 1. As illustrated in FIG. 13 , when a blind spot due to an obstacleis produced in the field of view of a monitoring camera, the monitoringsystem 1000 described in PTL 1 detects that a person has come into theblind spot and makes a notification to that effect. This allows, forexample, a security guard who uses the monitoring system 1000 to find asuspicious person present in the blind spot in a video captured by themonitoring camera.

CITATION LIST Patent Literature

-   [PTL 1] WO 2016/147704 A-   [PTL 2] JP 2011-048736 A-   [PTL 3] JP 2009-251761 A-   [PTL 4] WO 2010/131331 A

SUMMARY OF INVENTION Technical Problem

Depending on the orientation of the line of sight or the face of thesecurity guard, the blind spot of the security guard varies, andaccordingly, a region out of the field of view of the security guard canbe produced. In the prior art described in PTL 1, since the field ofview of the security guard is not considered and therefore a blind spotout of the field of view of the security guard cannot be detected, thereis a possibility of overlooking a suspicious person present in the blindspot of the security guard or suspicious behavior that has occurred inthe blind spot of the security guard.

PTLs 2 to 4 do not disclose presenting a region out of the field of viewof the security guard in relation to the monitoring system.

It is a primary object of the disclosure to present a region that is notfully monitored.

Solution to Problem

In order to solve the above problem, a monitoring device according toone aspect of the disclosure includes: a detection unit that detects aperson from an image; an estimation unit that estimates a region that isbeing viewed by the detected person; a determination unit thatdetermines, based on the estimated region, a region that requiresspecial attention within a monitoring area; and a presentation unit thatpresents information indicating the determined region that requiresspecial attention.

In order to solve the above problem, a monitoring method according toone aspect of the disclosure includes: detecting a person from an image;estimating a region that is being viewed by the detected person;determining, based on the estimated region, a region that requiresspecial attention within a monitoring area; and presenting informationindicating the determined region that requires special attention.

In order to solve the above problem, a recording medium according to oneaspect of the disclosure stores a program that causes a computer toexecute: detecting a person from an image; estimating a region that isbeing viewed by the detected person; determining, based on the estimatedregion, a region that requires special attention within a monitoringarea; and presenting information indicating the determined region thatrequires special attention.

Advantageous Effects of Invention

According to one aspect of the disclosure, a region that is not fullymonitored can be presented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an example of a configuration ofa monitoring system according to a first example embodiment.

FIG. 2 is a block diagram illustrating an example of a configuration ofan image processing device included in the monitoring system accordingto the first example embodiment.

FIG. 3 is a flowchart illustrating a flow of a process executed by theimage processing device according to the first example embodiment.

FIG. 4 is a diagram explaining an example of a method of determining aline of sight of a person.

FIG. 5 is a diagram explaining an example of a blind spot region.

FIG. 6 is a diagram explaining another example of the blind spot region.

FIG. 7 is a diagram explaining still another example of the blind spotregion.

FIG. 8A is a diagram explaining an example of the presentation of theblind spot region.

FIG. 8B is a diagram explaining an example of the presentation of theblind spot region.

FIG. 8C is a diagram explaining an example of the presentation of theblind spot region.

FIG. 8D is a diagram explaining an example of the presentation of theblind spot region.

FIG. 8E is a diagram explaining an example of the presentation of theblind spot region.

FIG. 9 is a diagram illustrating an example of a monitoring monitor ofthe monitoring system according to the first example embodiment.

FIG. 10A is a view illustrating an example of an eyewear-type deviceincluding a compact camera according to a second example embodiment.

FIG. 10B is a view illustrating an example of a cap-type deviceincluding a compact camera according to the second example embodiment.

FIG. 11 is a block diagram illustrating an example of a configuration ofa monitoring device according to a fourth example embodiment.

FIG. 12 is a diagram illustrating a hardware configuration of a deviceaccording to a fifth example embodiment.

FIG. 13 is a diagram explaining related art.

EXAMPLE EMBODIMENT First Example Embodiment

A first example embodiment of the disclosure will be described belowwith reference to FIGS. 1 to 9 .

(Monitoring System 1)

FIG. 1 is a block diagram illustrating a configuration of a monitoringsystem 1 according to the present first example embodiment. Themonitoring system 1 is used, for example, to monitor an event venue, agame hall, a resort, or a public place. As illustrated in FIG. 1 , themonitoring system 1 includes a monitoring camera 10, an image processingdevice 20, a wireless terminal 30 (for a security guard), and amonitoring monitor 40. The image processing device 20 is an example of amonitoring device.

The number of monitoring cameras 10 can be one or more. The orientationof the monitoring camera 10 may be fixed or movable. The monitoringcamera 10 captures an image of a space to be monitored (referred to as amonitoring area). The monitoring camera 10 according to the presentexample embodiment can capture a moving image. The monitoring camera 10transmits data of a captured video (including a moving image) to theimage processing device 20 and the monitoring monitor 40.

The image processing device 20 analyzes the video captured by themonitoring camera 10, and outputs an analysis result to the monitoringmonitor 40. Specifically, the image processing device 20 estimates aregion (hereinafter referred to as a blind spot region) in themonitoring area out of the field of view of a person, in accordance witha flow to be described later. The blind spot region is an example of aregion that requires special attention, and is included in a region thatis not viewed by the person. The field of view here indicates a regionthat can be viewed by the person.

The image processing device 20 transmits information indicating theblind spot region to the monitoring monitor 40 in a wireless or wiredmanner. The image processing device 20 also has a function of catching aperson who entered the blind spot region or an object left in the blindspot region, and when catching such a person or object, notifies thewireless terminal 30 of information relating to the catching by wirelesscommunication. A process executed by the image processing device 20 willbe described in detail later.

The wireless terminal 30 has a wireless communication function, and canperform wireless communication with the image processing device 20. Thewireless terminal 30 may be, for example, a transceiver. The wirelessterminal 30 is carried or worn by a security guard. The security guardmay further carry or wear an imaging device. Alternatively, the wirelessterminal 30 may include an imaging unit. In this case, data of a videocaptured by the imaging device or the imaging unit is transmitted to themonitoring monitor 40 via the image processing device 20 by wirelesscommunication.

The monitoring monitor 40 is always connected to the monitoring camera10, and displays a video captured by the monitoring camera 10 in realtime. The monitoring monitor 40 also displays a video captured by theimaging device carried or worn by the security guard. Normally, a personwho issues a command to the security guard (referred to as a commander)gazes at the video of the monitoring area displayed on the monitoringmonitor 40.

(Image Processing Device 20)

FIG. 2 is a block diagram illustrating a configuration of the imageprocessing device 20. As illustrated in FIG. 2 , the image processingdevice 20 includes, as functional units, a person detection unit 21, aline-of-sight determination unit 22, a field-of-view estimation unit 23,a blind spot region determination unit 24, and a presentation unit 28.Furthermore, the presentation unit 28 includes a notification unit 25and a display control unit 26. The person detection unit 21 is anexample of a detection means. The field-of-view estimation unit 23 is anexample of an estimation means. The blind spot region determination unit24 is an example of a determination means. The presentation unit 28 isan example of a presentation means.

Hereinafter, an example of a process executed by the image processingdevice 20 (hereinafter referred to as a blind spot region determinationprocess) will be described. At the same time, an example of eachoperation executed by the multiple functional units of the imageprocessing device 20 illustrated in FIG. 2 will also be described.

(Blind Spot Region Determination Process)

With reference to FIG. 3 , the flow of the blind spot regiondetermination process executed by the image processing device 20 will bedescribed together with the operation of each functional unit of theimage processing device 20. FIG. 3 is a flowchart illustrating a flow ofthe blind spot region determination process.

As illustrated in FIG. 3 , the person detection unit 21 of the imageprocessing device 20 acquires data of a video (here, a moving image isassumed) captured by the monitoring camera 10 (51).

Then, the person detection unit 21 detects a region of a person from aplurality of images (frame images) constituting the acquired video, andfurther detects a region of the face of the person from the region ofthe person in the images (S2).

The line-of-sight determination unit 22 detects, for example, a pupil ofthe person from the region of the face of the person extracted from theimages by the person detection unit 21. In addition, the line-of-sightdetermination unit 22 also determines the orientation of the face of theperson detected by the person detection unit 21. The line-of-sightdetermination unit 22 calculates the orientation of the line of sightfrom the orientation of the face of the person and the position of thepupil in the eye (S3).

FIG. 4 illustrates an example of a method of determining a line of sightof the person. In the present example embodiment, the line-of-sightdetermination unit 22 extracts a region of an eye of the person from theimage region of the face of the person detected by the person detectionunit 21 from the captured image including the person taken by themonitoring camera 10. Then, the line-of-sight determination unit 22determines the line of sight of the person using an eye trackingtechnology. The eye tracking technology employed here is not limited,and the description thereof will be omitted. The line-of-sightdetermination unit 22 can also determine the orientation of the line ofsight of the person, using an image of the person captured by a secondcamera different from the monitoring camera 10 (see a second exampleembodiment).

The field-of-view estimation unit 23 estimates the field of view of theperson from the orientation of the line of sight and the face of theperson determined by the line-of-sight determination unit 22 (S4). Inmore detail, the field-of-view estimation unit 23 estimates the field ofview of the person detected by the person detection unit 21, based onthe orientation of the line of sight and the face of the person, andangle information representing the field of view of the person given inadvance. The field of view represents a range that a person can see withan eye of the person.

In the present example embodiment, the angle information representingthe field of view of the person (hereinafter referred to asfield-of-view angle information) stored in advance by the imageprocessing device 20 is angle information on the field of view of anaverage person (for example, about 180 degrees in the horizontaldirection and about 60 degrees in the vertical direction).

The blind spot region determination unit 24 determines a region out ofthe field of view of the person estimated by the field-of-viewestimation unit 23 in the monitoring area (S5). At this time, the regiondetermined by the blind spot region determination unit 24 is referred toas a blind spot region. The blind spot region is not limited only to theregion out of the field of view of the person. Some examples of theblind spot region will be described later.

The display control unit 26 displays information indicating the blindspot region determined by the blind spot region determination unit 24 onthe monitoring monitor 40 (S6). An example of the presentation of theblind spot region will be indicated later. The notification unit 25 ofthe image processing device 20 may issue an alert to the wirelessterminal 30 carried or worn by the security guard to notify the wirelessterminal 30 that the monitoring area contains a blind spot region. Thus,the blind spot region determination process ends.

As described above, the image processing device 20 analyzes the imageacquired from the monitoring camera 10 to determine the blind spotregion, and displays information on the blind spot region on themonitoring monitor 40. A person watching the monitoring monitor 40, forexample, the commander, can check whether there is a suspicious personor a suspicious object in the blind spot region by gazing at themonitoring monitor 40, or can instruct a security guard to check theblind spot region. This is deemed to have an effect of suppressing anincident or an accident in the blind spot region.

(First Modification of Blind Spot Region Determination Process)

In one modification, in step S2 (the detection of the face of theperson) in FIG. 3 , the person detection unit 21 recognizes the face ofa particular person (security guard) instead of any person, using animage captured by the monitoring camera 10. The security guard is aperson who patrols in the monitoring area and checks whether a case suchas an incident or an accident is occurred.

In the present modification, the person detection unit 21 collates theface image of the security guard stored in the image processing devicewith the face of a person detected from an image captured by themonitoring camera 10. When the collation fails, that is, when the persondetected from the image by the person detection unit 21 is not thesecurity guard, the person detection unit 21 repeats the process in stepS2 in FIG. 3 .

On the other hand, when the collation is successful, the blind spotregion determination process proceeds to step S3 in FIG. 3 . The flowfrom step S3 in the present modification is as illustrated in FIG. 3 .That is, the blind spot region of the security guard is determined, andthe determined blind spot region is displayed on the monitoring monitor40.

According to the configuration of the present modification, the blindspot region of the security guard is displayed on the monitoring monitor40. Therefore, the commander gazing at the monitoring monitor can easilyknow a region that is not fully monitored by the security guard. Then,the commander can issue an appropriate command to the security guard.

(Second Modification of Blind Spot Region Determination Process)

In another modification, after step S5 (the determination of the blindspot region) in FIG. 3 , when the blind spot region determination unit24 determines that there is a region that does not enter the field ofview of a person (for example, the security guard) beyond apredetermined time, the blind spot region determination unit 24instructs the notification unit 25 to make a notification. Thenotification unit 25 that accepted the instruction from the blind spotregion determination unit 24 issues an alarm to the wireless terminal 30carried by the security guard. This allows the security guard to knowthat there is a region desired to be viewed.

(Third Modification of Blind Spot Region Determination Process)

In still another modification, in step S4 (the estimation of the fieldof view of the person) in FIG. 3 , the field-of-view estimation unit 23may detect the orientation of the face of the person detected by theperson detection unit 21, using an inertial sensor or an orientationsensor such as a gyro sensor (not illustrated) carried or worn on thehead or the shoulder by the person. For example, the orientation of theface of the person may be detected by designating a reference directionin advance and working out a direction in which the face of the personmoved from the reference direction, based on a value acquired by theinertial sensor and information on the reference direction. In thiscase, the field-of-view estimation unit 23 estimates that theorientation of the line of sight is the front of the face. Thefield-of-view estimation unit 23 estimates the field of view of theperson, based on the orientation of the line of sight estimated in thismanner and the field-of-view angle information on an average human.

In the present modification, the line-of-sight determination unit 22does not need to determine the orientation of the line of sight of theperson.

(Fourth Modification of Blind Spot Region Determination Process)

In still another modification, in step S4 (the estimation of the fieldof view of the person) in FIG. 3 , the field-of-view estimation unit 23estimates a region viewed by the person, based on the flow line of theperson detected by the person detection unit 21.

In the present modification, the person detection unit 21 includes atracking unit 29. That is, the person detection unit 21 detects theimage region of the person and tracks the person in the detected imageregion in step S2 in FIG. 3 by the function of the tracking unit 29. Thetracking unit 29 is an example of a tracking means. Then, the persondetection unit 21 sends a result of tracking the person (including flowline information) to the field-of-view estimation unit 23. Thefield-of-view estimation unit 23 estimates a predetermined region nearthe position of the person as the field of view of the person.

In the present modification, as the person moves, the field of view ofthe person also moves.

Also in the present modification, step S3 (the determination of the lineof sight of the person) in FIG. 3 is omitted. That is, in the presentmodification, the line-of-sight determination unit 22 does not need todetermine the orientation of the line of sight or the face of theperson.

(Example of Blind Spot Region)

Some examples of the above-described blind spot region will be describedbelow.

(Specific Example 1 of Blind Spot Region)

FIG. 5 is a diagram illustrating an example of the blind spot region. Aperson can view regions of each up to about 50 degrees on both of theleft and right sides with the orientation of the line of sight of theperson as the center. The region that can be viewed by the person isreferred to as a field of view of the person. In the example illustratedin FIG. 5 , in the monitoring area, a region V₁ (an unhatched region inFIG. 5 ) extending ahead of the person represents the field of view ofthe person. In FIG. 5 , a region D₁ illustrated as hatched regiondenotes the blind spot region in the present example. A rectangularframe line A surrounding the person represents the monitoring area. Thatis, in the monitoring area, a region (the hatched region in FIG. 5 ) outof the field of view of the person corresponds to the blind spot regionin the present example.

(Specific Example 2 of Blind Spot Region)

FIG. 6 is a diagram illustrating another example of the blind spotregion. In the example illustrated in FIG. 6 , similarly to the exampleillustrated in FIG. 5 , a rectangular frame line A surrounding theperson represents the monitoring area. Then, in FIG. 6 , a region D2 outof the field of view of the person denotes a first blind spot region,and an unhatched area V₂ denotes the field of view of the person. Inaddition, in the example illustrated in FIG. 6 , a region D3 that isinvisible from the person due to the line of sight of the person beingblocked by an obstacle denotes a second blind spot region. The firstblind spot region D2 and the second blind spot region D3 are alsoexamples of the region that requires special attention, and are includedin regions that are not viewed by the person.

For example, the blind spot region determination unit 24 of the imageprocessing device 20 detects an object present in the monitoring area orin the field of view of the person, that is, an obstacle, from a videocaptured by the monitoring camera 10. Then, the blind spot regiondetermination unit 24 determines a region shielded from the line ofsight of the person by the obstacle, as the second blind spot region D3illustrated in FIG. 6 .

(Specific Example 3 of Blind Spot Region)

FIG. 7 is a diagram illustrating still another example of the blind spotregion. In the example illustrated in FIG. 7 , a region V3 surrounded bya dashed-dotted line represents the field of view of the person, and aregion V4 surrounded by a dashed-double-dotted line represents the fieldof view of the monitoring camera 10. A region D4 outside the field ofview of the person and also outside the field of view of the monitoringcamera 10 denotes the blind spot region. In other words, a region thatcannot be viewed by the person and also by the commander or the like(see FIG. 9 ) gazing at the monitoring monitor 40 corresponds to theblind spot region in the present example.

In the present example, for example, information on the orientation ofthe monitoring camera 10 resolved according to the installation form ofthe monitoring camera 10 is given in advance to the monitoring cameraand the blind spot region determination unit 24 of the image processingdevice 20 acquires that information from the monitoring camera 10 todetermine the field of view of the monitoring camera 10, based on theacquired information. Then, the blind spot region determination unit 24determines a region that is out of the field of view of the person andalso out of the field of view of the monitoring camera that captures animage of the monitoring area, as a blind spot region.

(Specific Example 1 of Presentation of Blind Spot Region)

Specific examples of the presentation of the blind spot region by thedisplay control unit 26 will be described with reference to FIGS. 8A to8E. FIGS. 8A to 8E illustrate maps of the monitoring area displayed on ascreen of a display apparatus by the display control unit 26. Thedisplay apparatus may be the monitoring monitor 40 or another displayapparatus (not illustrated). For example, the screens illustrated inFIGS. 8A to 8E are displayed on a display device carried by a person(security guard) patrolling in the monitoring area.

In the present example, the blind spot region varies as the person movesin the monitoring area. At this time, even if a region that entered thefield of view of the person thereafter becomes out of the field of viewof the person, the region is not presented as a blind spot region withina predetermined time. FIGS. 8A to 8E are arranged in time series in thisorder. In FIGS. 8A to 8E, the blind spot region is indicated as ahatched region. An obstacle is indicated as a filled region. Therelationship between the field of view of the person, the obstacles, andthe blind spot regions in FIGS. 8A to 8E is an example. The field ofview of the person illustrated in the present example is an example andis not restricted to the present example.

In FIG. 8A, the person is present at the lower left of the monitoringarea in the drawing. An arrow in FIG. 8A represents the line of sight ofthe person. The person is looking at the upper left side of themonitoring area in the drawing. The blind spot region at this time isdenoted by a hatched region D5 obtained by excluding the left side ofthe monitoring area in the drawing.

In FIG. 8B, the person stays at the lower left of the monitoring area inthe drawing. An arrow in FIG. 8B faces the right side in the drawing.That is, the person is looking at the lower right of the monitoring areain the drawing. The blind spot region at this time is denoted by ahatched region D₆ containing a central portion and the upper right ofthe monitoring area in the drawing.

In FIG. 8C, the person is moving to the upper side of a central portionof the monitoring area in the drawing. As indicated by an arrow in FIG.8C, the person is looking at the upper right of the monitoring area inthe drawing. The blind spot region at this time is denoted by a hatchedregion D₇ containing a central portion and the right side of themonitoring area in the drawing.

In FIG. 8D, the person directs his/her line of sight toward the lowerside of a central portion of the monitoring area in the drawing. Theblind spot region at this time is denoted by a hatched region Dg on theright side of the monitoring area in the drawing.

In FIG. 8E, the person is moving to the lower right of the monitoringarea in the drawing by passing through the upper right of the monitoringarea in the drawing. No blind spot region remains.

In the present example, the person detection unit 21 of the imageprocessing device 20 tracks the person. Every predetermined time orevery time the orientation of the line of sight changes, theline-of-sight determination unit 22 calculates the real-time orientationof the line of sight of the person being tracked. The field-of-viewestimation unit 23 estimates the field of view of the person beingtracked every time the line-of-sight determination unit 22 calculatesthe orientation of the line of sight of the person.

The blind spot region determination unit 24 determines a region that isnot viewed by the person being tracked within a predetermined time afterthe starting time point of tracking the person, based on the field ofview of the person estimated by the field-of-view estimation unit 23.The blind spot region determination unit 24 converts the determinedregion in the real space that is not viewed by the person being trackedinto a blind spot region as a region in the map of the monitoring area.

The display control unit 26 generates, for example, the screensillustrated in FIGS. 8A to 8E, based on information on the blind spotregion converted into a region in the map of the monitoring area by theblind spot region determination unit 24, and displays the generatedscreens on the display device carried by the person. This allows theperson to easily grasp an area that the person has not viewed yet, thatis, the blind spot region, by checking the screens in FIGS. 8A to 8Edisplayed on the display device.

(Second Specific Example of Presentation of Blind Spot Region)

FIG. 9 is a diagram illustrating an example of the monitoring monitor 40according to the present example embodiment. As illustrated in FIG. 9 ,the monitoring monitor 40 according to the present example embodiment isconstituted by, for example, a plurality of display units. A pluralityof monitoring cameras 10 captures images of the monitoring area fromdirections different from each other. The multiple display units of themonitoring monitor 40 simultaneously display videos received from themonitoring cameras 10 different from each other in real time. However,the monitoring monitor 40 may include only one display unit. In thiscase, the monitoring monitor 40 may sequentially display videos receivedfrom a plurality of monitoring cameras 10. In the present example, it isassumed that the entire monitoring area is displayed on the monitoringmonitor 40 by the plurality of display units.

As described above in specific example 1, the blind spot regiondetermination unit 24 determines a region that has not yet entered thefield of view of the person, as a blind spot region, based on the fieldof view of the person estimated by the field-of-view estimation unit 23.The blind spot region determination unit 24 converts the determinedblind spot region in the real space into a blind spot region in the mapof the monitoring area displayed on the screen.

The blind spot region determination unit 24 specifies a display unitrelevant to the blind spot region in the map of the monitoring area,based on a relationship between a display unit and a partial region inthe map of the monitoring area displayed by this display unit. In otherwords, the blind spot region determination unit 24 specifies an imageregion showing the blind spot region from the entire image displayed bythe monitoring monitor 40.

The display control unit 26 displays the image region showing the blindspot region specified by the blind spot region determination unit 24, onthe monitoring monitor 40 in a more conspicuous mode or in a moreemphasized manner than other image regions. In FIG. 9 , the image regionshowing the blind spot region is emphasized by light emission orblinking.

By watching the monitoring monitor 40, the commander can quickly noticethat a blind spot region occurred in the monitoring area. The commandercan contact the wireless terminal 30 of the security guard using acommunication device (not illustrated) and instruct the security guardlocated in or in the vicinity of the monitoring area to immediatelycheck the blind spot region.

Second Example Embodiment

Another example embodiment of the disclosure will be described below.

In the present second example embodiment, a case where the monitoringsystem is used in a circumstance where a lifeguard keeps constantmonitoring, such as a swimming pool or a swimming area, will bedescribed. The basic configuration of a monitoring system according tothe present second example embodiment is the same as the configurationof the monitoring system 1 according to the first example embodimentillustrated in FIG. 1 .

(Monitoring System 1 of Second Example Embodiment)

In the present second example embodiment, a lifeguard of a swimming poolor a swimming area wears a cap-type or eyewear-type device 50 a or 50 b(see FIGS. 10A and 10B) having a wireless communication function.

As illustrated in FIGS. 10A and 10B, the cap-type or eyewear-type device50 a or 50 b includes a compact camera 51. The compact camera 51 facesthe face of the lifeguard wearing the cap-type or eyewear-type device 50a or 50 b. A line-of-sight determination unit 22 (see FIG. 2 ) of animage processing device 20 acquires, from the device 50 a or 50 b, animage in which the eye of the lifeguard and the surroundings of the eyeare captured. Then, the line-of-sight determination unit 22 determinesthe line of sight of the lifeguard using an eye tracking technology.

As in the first example embodiment, a field-of-view estimation unit 23estimates the field of view of the lifeguard, based on the line of sightof the lifeguard. Also as in the first example embodiment, a blind spotregion determination unit 24 determines a blind spot region out of thefield of view of the lifeguard, based on the field of view of thelifeguard. The blind spot region determination unit 24 sends informationon the determined blind spot region to a notification unit 25.

The notification unit 25 detects a swimmer from a video captured by amonitoring camera 10. Then, when a swimmer is present in the blind spotregion determined by the blind spot region determination unit 24, thenotification unit 25 issues an alarm to the lifeguard.

Effects of Second Example Embodiment

According to the configuration of the present example embodiment, sincethe lifeguard can be made to notice a swimmer present in the blind spotregion, the possibility of the occurrence of a water accident in theswimming pool or the swimming area can be reduced.

Application Example to Above-Described First Example Embodiment

The method of determining the line of sight of a person described in thepresent second example embodiment can be applied to the above-describedfirst example embodiment. That is, in step S3 (the determination of theline of sight of the person) of the blind spot region determinationprocess illustrated in FIG. 3 , the line-of-sight determination unit 22may determine the line of sight of a person using an image captured bythe compact camera 51 attached to the cap-type or eyewear-type device 50a or 50 b worn by the person, instead of an image captured by themonitoring camera 10.

Third Example Embodiment

Another example embodiment of the disclosure will be described below.

In the present third example embodiment, a case where the monitoringsystem is used in a retail shop will be described. The basicconfiguration of a monitoring system according to the present thirdexample embodiment is the same as the configuration of the monitoringsystem 1 according to the first example embodiment illustrated in FIG. 1.

In the present third example embodiment, a person detection unit 21 ofan image processing device 20 detects a sales clerk present in a shop,which is a monitoring area. A field-of-view estimation unit 23calculates the density of the number of sales clerks per partial regionin the shop (hereinafter referred to as a density of sales clerks), andestimates a region having a higher density of sales clerks than athreshold value, as having been viewed by a sales clerk. A blind spotregion determination unit 24 (see FIG. 2 ) determines a region having alower density of sales clerks than the threshold value in the shop, as ablind spot region. The threshold value may be set in any manner. In thepresent third example embodiment, a line-of-sight determination unit 22may not determine the line of sight of the sales clerk detected by theperson detection unit 21.

The person detection unit 21 detects a customer (or a person apart fromthe sales clerks) in the blind spot region determined by the blind spotregion determination unit 24, using information on the sales clerksgiven in advance. A notification unit 25 issues an alarm to a salesclerk or the like by an announcement, wireless communication, or thelike, with the detection of a customer in a blind spot region by theperson detection unit 21 as a trigger.

As described above, in the present third example embodiment, a regionbeing viewed by a sales clerk is estimated based on the density of salesclerks. In a region having a higher density of sales clerks (than thethreshold value), it is estimated that at least one sales clerk willnotice the presence of a customer. On the other hand, in a region havinga lower density of sales clerks (than the threshold value), there is apossibility that no sales clerk notices the presence of a customer. As aresult, a situation in which a customer service is not provided to thecustomer for a long time can be produced. However, in the present thirdexample embodiment, since the notification unit 25 issues an alarm to asales clerk in a region having a lower density of sales clerks than thethreshold value, it is possible to prevent such a situation fromoccurring and to prevent loss of sales opportunities.

Effects of Third Example Embodiment

According to the configuration of the present example embodiment, asales clerk can be made to notice a customer present in the blind spotregion. Furthermore, there is also an effect of avoiding a customer fromattempting shoplifting.

Fourth Example Embodiment

Another example embodiment of the disclosure will be described below.

(Monitoring Device 220)

FIG. 11 is a block diagram illustrating a configuration of a monitoringdevice 220 according to the present fourth example embodiment. Asillustrated in FIG. 11 , the monitoring device 220 includes a detectionunit 221, an estimation unit 222, a determination unit 223, and apresentation unit 224.

For example, the detection unit 221 acquires an image of the inside ofthe monitoring area captured by a monitoring camera. The detection unit221 detects a person from the acquired image.

The estimation unit 222 estimates a region being viewed by the persondetected by the detection unit 221. The region being viewed by theperson refers to a region included in the field of view of the person.The estimation unit 222 detects the line of sight of the person in theimage using, for example, a widely known line-of-sight detectiontechnology. Then, the estimation unit 222 calculates the field of viewof the person, using the orientation of the detected line of sight ofthe person and the angle information on the field of view of an averagehuman. The estimation unit 222 estimates a region included in thecalculated field of view of the person, as a region being viewed by theperson.

The determination unit 223 determines a region that requires specialattention within the monitoring area, based on the region estimated bythe estimation unit 222. The region that requires special attention is,for example, the blind spot region described in the first to thirdexample embodiments.

The presentation unit 224 presents information indicating the regionthat requires special attention determined by the determination unit223. A means for the presentation is not particularly limited. Forexample, the presentation unit 224 displays a map on which the regionthat requires special attention is indicated, on a display apparatus.Alternatively, the presentation unit 224 uses a warning light or aspeaker to make a notification on the presence of the region thatrequires special attention.

Effects of Fourth Example Embodiment

According to the configuration of the present example embodiment, aregion being viewed by a person is estimated, and the region thatrequires special attention within the monitoring area is determined. Forexample, in the monitoring area, a region that is not viewed by a personis determined to be the region that requires special attention. Then,information indicating the determined region that requires specialattention is presented. This allows to present a region that is notfully monitored, that is, the region that requires special attention, toa person such as a commander or a security guard.

Fifth Example Embodiment

Another example embodiment of the disclosure will be described below.

(Regarding Hardware Configuration)

In each example embodiment of the present disclosure, each constituentelement of each device indicates a block in units of functions. Some orall of multiple constituent elements of each device may be achieved byany combination of a device 900 and a program as illustrated in FIG. 12, for example. FIG. 12 is a block diagram illustrating an example of ahardware configuration of the device 900 that achieves each constituentelement of each device.

As illustrated in FIG. 12 , the device 900 includes the followingcomponents as an example.

-   -   Central processing unit (CPU) 901    -   Read only memory (ROM) 902    -   Random access memory (RAM) 903    -   Program 904 that is loaded into RAM 903    -   Storage device 905 that stores program 904    -   Drive device 907 that performs reading and writing on recording        medium 906    -   Communication interface 908 connected to communication network        909    -   Input/output interface 910 that inputs and outputs data    -   Bus 911 that connects between respective constituent elements

Each constituent element of each device in each example embodiment isachieved by the CPU 901 acquiring and executing the program 904 thatenables the functions of these constituent elements. The program 904that enables the function of each constituent element of each device isstored in advance, for example, in the storage device 905 or the ROM902, and is loaded into the RAM 903 and executed by the CPU 901 asnecessary. The program 904 may be supplied to the CPU 901 via thecommunication network 909, or may be stored in advance in the recordingmedium 906 in such a way as to be supplied to the CPU 901 by the drivedevice 907 that read out the stored program.

Effects of Fifth Example Embodiment

According to the configuration of the present example embodiment, thedevice described in any one of the above example embodiments is achievedas hardware. Therefore, effects similar to the effects described in anyof the above example embodiments can be obtained.

While the disclosure has been particularly shown and described withreference to example embodiments thereof, the disclosure is not limitedto these example embodiments. It will be understood by those of ordinaryskill in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the disclosure asdefined by the claims.

[Supplementary Note]

Some or all of the above example embodiments can also be described as inthe following supplementary notes, but are not restricted to thefollowing.

(Supplementary Note 1)

A monitoring device including:

-   -   a detection unit that detects a person from an image;    -   an estimation unit that estimates a region that is being viewed        by the detected person;    -   a determination unit that determines, based on the estimated        region, a region that requires special attention within a        monitoring area; and    -   a presentation unit that presents information indicating the        determined region that requires special attention.

(Supplementary Note 2)

The monitoring device according to supplementary note 1, in which

-   -   the detection unit acquires the image from a monitoring camera        that captures an image of the monitoring area.

(Supplementary Note 3)

The monitoring device according to supplementary note 1 or 2, in which

-   -   the detection unit detects a particular person from the image,        and    -   the estimation unit estimates a region that is being viewed by        the particular person, using a sensor carried or worn by the        particular person.

(Supplementary Note 4)

The monitoring device according to any one of supplementary notes 1 to3, in which

-   -   the detection unit further detects an object other than the        person, and    -   the estimation unit determines a region within the monitoring        area that is shielded from a line of sight of the person by the        detected object, as not being viewed by the person.

(Supplementary Note 5)

The monitoring device according to any one of supplementary notes 1 to4, in which

-   -   the determination unit determines a region that is out of a        field of view of the person and also out of a field of view of a        monitoring camera that captures an image of the monitoring area,        as the region that requires special attention.

(Supplementary Note 6)

The monitoring device according to any one of supplementary notes 1 to5, in which

-   -   the detection unit includes a tracking unit that track the        person, and    -   the estimation unit estimates the region that is being viewed by        the person, based on a result of tracking the person by the        tracking unit.

(Supplementary Note 7)

The monitoring device according to any one of supplementary notes 1 to6, further including

-   -   a line-of-sight determination unit that determines a line of        sight of the person detected by the detection unit, in which    -   the estimation unit estimates a field of view of the person,        based on the determined line of sight of the person.

(Supplementary Note 8)

The monitoring device according to supplementary note 7, in which

-   -   the line-of-sight determination unit determines the line of        sight of the person, using an image from which the person        detected by the detection unit.

(Supplementary Note 9)

The monitoring device according to supplementary note 7, in which

-   -   the detection unit detects a particular person from the image,        and    -   the line-of-sight determination unit determines a line of sight        of the particular person, using an image captured by a device        carried or worn by the particular person.

(Supplementary Note 10)

The monitoring device according to any one of supplementary notes 1 to9, in which

-   -   the detection unit detects a particular person from the image,    -   the monitoring device further including a notification unit that        notifies the particular person detected by the detection unit        that the monitoring area contains the region that requires        special attention.

(Supplementary Note 11)

The monitoring device according to any one of supplementary notes 1 to10, in which

-   -   the presentation unit displays the region that requires special        attention, on a display apparatus in an aspect different from        aspects for other regions of the monitoring area.

(Supplementary Note 12)

A monitoring method including:

-   -   detecting a person from an image;    -   estimating a region that is being viewed by the detected person;    -   determining, based on the estimated region, a region that        requires special attention within a monitoring area; and    -   presenting information indicating the determined region that        requires special attention.

(Supplementary Note 13)

A program for causing a computer to execute:

-   -   detecting a person from an image;    -   estimating a region that is being viewed by the detected person;    -   determining, based on the estimated region, a region that        requires special attention within a monitoring area; and    -   presenting information indicating the determined region that        requires special attention.

This application is based upon and claims the benefit of priority fromJapanese patent application No. 2019-003514, filed on Jan. 11, 2019, thedisclosure of which is incorporated herein in its entirety by reference.

REFERENCE SIGNS LIST

-   -   1 monitoring system    -   monitoring camera    -   image processing device    -   21 person detection unit    -   22 line-of-sight determination unit    -   23 field-of-view estimation unit    -   24 blind spot region determination unit    -   25 notification unit    -   26 display control unit    -   28 presentation unit    -   29 tracking unit    -   30 wireless terminal    -   40 monitoring monitor    -   220 monitoring device    -   221 detection unit    -   222 estimation unit    -   223 determination unit    -   224 presentation unit

1. A monitoring device comprising: a memory; and at least one processorcoupled to the memory, the at least one processor performing operationsto: detect a person from an image; estimate, based on density of numberof persons per partial region in a monitoring area, a region having thedensity being higher than threshold value as a region that is beingviewed by the detected person; determine, as a region that requiresspecial attention, a region differ from the estimated region within amonitoring area; and present information indicating the determinedregion that requires special attention.
 2. The monitoring deviceaccording to claim 1 wherein the at least one processor further performsoperation to: determine, as the region that requires special attention,a region having the density being lower than the threshold value.
 3. Themonitoring device according to claim 1 wherein the at least oneprocessor further performs operation to: detect a particular persondiffer from the person from the image; and when the particular person ispresent in the determined region, issue an alarm to the person.
 4. Themonitoring device according to claim 3 wherein the monitoring area is ina shop, the person is a sales clerk, the particular person is acustomer; and the at least one processor further performs operation to:when the customer is present in the determined region, issue an alarm tothe salesclerk.
 5. The monitoring device according to claim 1, whereinthe at least one processor further performs operation to: display a mapindicating the region that requires special attention within themonitoring area.
 6. The monitoring device according to claim 5, whereinthe at least one processor further performs operation to: display themap indicating the region that requires special attention with changesaccording to movement of the detected person.
 7. A monitoring methodcomprising: detecting a person from an image; estimating, based ondensity of number of persons per partial region in a monitoring area, aregion having the density being higher than threshold value as a regionthat is being viewed by the detected person; determining, as a regionthat requires special attention, a region differ from the estimatedregion within a monitoring area; and presenting information indicatingthe determined region that requires special attention.
 8. The monitoringmethod according to claim 7, wherein the monitoring method comprises:determining, as the region that requires special attention, a regionhaving the density being lower than the threshold value.
 9. Themonitoring method according to claim 7, wherein the monitoring methodcomprises: detecting a particular person differ from the person from theimage; and when the particular person is present in the determinedregion, issuing an alarm to the person.
 10. The monitoring methodaccording to claim 9, wherein the monitoring area is in a shop, theperson is a salesclerk, the particular person is a customer; and themonitoring method comprises: when the customer is present in thedetermined region, issuing an alarm to the salesclerk.
 11. Themonitoring method according to claim 7, wherein the monitoring methodcomprises: displaying a map indicating the region that requires specialattention within the monitoring area.
 12. The monitoring methodaccording to claim 11, wherein the monitoring method comprises:displaying the map indicating the region that requires special attentionwith changes according to movement of the detected person.
 13. Arecording medium having recorded therein a program for causing acomputer to execute: detecting a person from an image; estimating, basedon density of number of persons per partial region in a monitoring area,a region having the density being higher than threshold value as aregion that is being viewed by the detected person; determining, as aregion that requires special attention, a region differ from theestimated region within a monitoring area; and presenting informationindicating the determined region that requires special attention. 14.The recording medium according to claim 13, wherein the program causesthe computer to execute: determining, as the region that requiresspecial attention, a region having the density being lower than thethreshold value.
 15. The recording medium according to claim 13, whereinthe program causes the computer to execute: detecting a particularperson differ from the person from the image; and when the particularperson is present in the determined region, issuing an alarm to theperson.
 16. The recording medium according to claim 15, wherein themonitoring area is in a shop, the person is a salesclerk, the particularperson is a customer; and the program causes the computer to execute:when the customer is present in the determined region, issuing an alarmto the salesclerk.
 17. The recording medium according to claim 13,wherein the program causes the computer to execute: displaying a mapindicating the region that requires special attention within themonitoring area.
 18. The recording medium according to claim 17, whereinthe program causes the computer to execute: displaying the mapindicating the region that requires special attention with changesaccording to movement of the detected person.